Flat panel display devices often operate using electron emitting structures, such as, for example, Spindt-type field emitters. These types of flat panel displays often employ a polyimide structure to focus or define the path of electrons emitted from the electron emitting structures. In one prior art approach, the polyimide structure is referred to as a "focus waffle." The structure is comprised of a plurality of rows which are parallel to each other and a plurality of columns which are parallel to each other but which are substantially orthogonal to the plurality of rows. The plurality of rows and columns of polyimide material define openings therebetween. The focus waffle is disposed between the electron emitting structures and the faceplate such that emitted electrons pass through openings in the focus waffle structure, and are directed towards corresponding sub-pixel regions.
Unfortunately, such prior art polyimide focus waffle structures are extremely expensive and, thus, introduce additional costs for flat panel display fabrication. As yet another disadvantage, such prior art polyimide focus waffle structures are a major source of contamination in flat panel display devices. That is, such "dirty" polyimide focus waffle structures introduce contaminate particles into the evacuated environment of the flat panel display device. These contaminate particles degrade the performance of the flat panel display device, may cause discoloration, and reduce the effective lifetime of the flat panel display device. In addition to emitting contaminate particles, such prior art focus waffle structures also outgas material (e.g. organics) due to electron desorbtion and thermal stresses induced during flat panel display fabrication steps.
As yet another drawback, the application of conductive coatings (e.g. aluminum) applied to polyimide focus waffle structures introduces considerable difficulty and complexity during the fabrication of conventional flat panel display devices. More specifically, in conventional flat panel display fabrication, the conductive coatings are applied using an angled evaporation process. The angled evaporation process is difficult, time-consuming, and expensive. In addition to being difficult to perform, the time-consuming nature of the angled evaporation process reduces throughput and yield during the fabrication of flat panel display devices.
Thus, a need exists for a focus waffle structure which does not suffer from significant expense, contaminate emission, and outgassing. A further need exists for a focus waffle structure which meets the above-listed need and also eliminates the requirement for complex and difficult angled evaporation processing steps. Still another need exists for a focus waffle structure which meets the above-listed needs and further improves focus waffle manufacturing throughput and yield.